Definitely - don't let my comment about adding features to increase staying power make you start thinking too far out of scope. :p Some of the things you mentioned, especially making the slow-mo more involved, I think would be a great direction to take it. Wobbling structures, breakable structures, timing (imagine needing two bullets to hit at the same time so you speed up/slow down one to match the position of the other that you fired previously), etc.
No matter what though, this definitely deserved the recognition it got from that game jam. I'll be leaving it in my library to remind me in the future in case it turns out you put out a full release. :)